Computer Systems

What is the purpose of a computer?

To take data, process and output it. Computers were made to help process data and complete tasks more efficiently than humans.

What is hardware?

The physical stuff that makes up your computer:

CPU

Motherboard

Monitor

What is software?

The programs that your computer runs on. There is application software which are programs that help the user perform specific tasks and there is system software which is operating systems.

What is an embedded system?

A computer built into other devices like microwaves and TVs. They are often used as control systems and are dedicated to single tasks.

What are the main parts of a computer?

Power supply

Case cooling fan

CPU heat sink and cooling fan

CPU

Optical drive

RAM sticks

Motherboard

Hard Disk Drive

What is the CPU?

The Central Processing Unit is the brain of the computer system. It processes all of the data for the system.

What are the 6 main parts of the CPU?

The Control Unit (CU)

The Arithmetic Logic Unit (ALU)

Cache

The Clock

Buses

Registers

The Control Unit

The overall control of the CPU. It manages the FDE cycle and controls the flow of data.

The Arithmetic Logic Unit

The ALU does all the simple calculations and logic operations. Registers store the immediate results.

Cache

The very fast memory in the CPU (slower then registers but faster then RAM) that stores regularly used data for quick access.

The Clock

It sends put a signal that continually cycles between 1 and 0 at a constant rate. This signal is used ti synchronise when instructions will be carried out. The number of clock cycles per second is called clock speed.

Buses

A collection of wires used to transmit data between components of the CPU and other parts of the computer system.

Registers

Storage that temporarily holds tiny bits of data needed by the CPU and are super quick.

What is the Fetch-Decode-Execute Cycle?

The FDE is what the CPU does to carry out instructions. It fetches the instruction from the memory and decodes it in the control unit and executes the instruction.

What are the four types if memory?

RAM

ROM

Cache

Registers

RAM

Random Access Memory is used as main memory and is volatile. It is where all data, files and programs are stored.

ROM

Read Only Memory is non-volatile memory that can only be read. It is the instructions for the computer to boot up.

What are the two types of storage?

Primary Storage - The memory areas that the CPU can access directly.

Secondary Storage - Non-volatile storage that isn’t directly accessed by the CPU.

What are HDDs?

Hard drive disks are the traditional internal storage in PCs and laptops. It is made up of magnetic metal disks and data is stored magnetically. It has a metal head which writes 0s and 1s on magnetic North or South.They are slow but reliable.

What are SSDs?

Solid State Drives have no moving parts. They store data in electrical circuits by trapping electrons in floating gate transistors. They are fast, reliable but expensive.

What are optical discs?

Optical Discs are things like DVDs or CDs. They store data in pits and lands. There are less popular now due to more advanced methods like streaming and downloading. They are cheap, portable but are easily scratched.

What are the main functions of an Operating System?

Communication with Input and Output devices:

It allows the computer to take inputs and outputs.

Provide a platform for applications to run on:

It manages applications and access hardware

Control memory management:

It manages all memory and RAM access

Organise the CPU:

Determines the most efficient order for the CPU

Manage System Security:

Controls many ways to keep stored data secure

What are some utilities of a computer?

Defragmentation - Rearranging files to create more space.

Disk Health - Scans the drive for problems and fixes issues.

System Cleanup - Deletes unnecessary files.

Compression - Reduces file sizes for space.

Virus Scanners - Used to inspect files.

What is a Translator?

A program that allows source code to be understood and executed by the computer.

What is the difference between High and Low level language?

High-Level Language:

One instruction represents many instructions of machine code. Easy for humans to understand but not computers as they must translate it. Easy to read, understand and modify.

Low-Level Language:

One instruction usually represents one instruction of machine code. Easy for computers to understand but not humans. Tricky to read, understand and modify.

What are Compilers, Interpreters and Assemblers?

Assemblers - Translates Assembly language to Machine code.

Compilers - Translates high-level language into Machine code.

Interpreters - Call machine code subroutines to carry out an instruction.